In order for fat loss to occur, the body has to be in an energy deficit. This means that we must consume less energy everyday then we burn. It’s pretty straight forward, if we burn 2500cals/day and only consume 2000, there are 500 that we burned from a source other than food. In an attempt to preserve muscle, our body turns to fat metabolism to supply energy once blood sugar and glycogen stores have been used up.
However, there is one major problem in this equation. Our Western diet revolves around multiple energy dense meals per day, meaning we are almost always burning glucose from the previous meal by the time we eat again and therefore storing excess as fat.
This is where intermittent fasting comes into play. Intermittent fasting provides a window of time designated for feeding (4-12h), and another window designated for fasting (12-24h+). The most common types used and therefore studied are 16 hour fasts with 8 hours feeding, and alternate day fast/feed.
Prolonged periods without food almost certainly guarantee that our body switches to fat metabolism, since it takes several hours after a meal for the food to be digested and absorbed and insulin levels to return to baseline.
Critics of IF will argue that it is too extreme and depriving yourself of nutrients will be harmful to the body, which couldn’t be further from the truth!
Major Benefits of IF
Improves insulin sensitivity. The body becomes more sensitive to the effects of insulin… less insulin secretion per meal… lower blood glucose and insulin levels!
Promotes autophagy. Regular bodily process where damaged, old, and dysfunctional proteins are consumed by the body. Think of renovating your kitchen, you need to tear away all the old cupboards before installing new ones!
Elevates Growth Hormone production. GH is very important hormone for body composition, because it releases stored fat and preserves muscle during fasting.
Reduced systemic inflammation. Inflammation occurs in the body after exposure to a variety of stimuli, including viruses, injury, certain foods, and even exercise. Chronic inflammation is a precursor to atherosclerosis, cardiovascular disease, and other harmful diseases.
Intermittent Fasting is also a great way to improve your body composition, as it’s proven to safely and effectively promote fat loss while providing additional major health benefits.
TRAINING WHILE FASTING ACCELERATES FAT LOSS!
After a typical 8-10 hour overnight fast, our glycogen stores become depleted and we are better able to mobilize and burn body fat for energy.
Combine this with an intense early morning training session before breakfast and you can really tap into those fat stores!
There two possible explanations as to why combining exercise and IF may be more beneficial than either on their own.
Increased lipolysis (breakdown of fats) and fat oxidation (using fatty acids for energy).
Male participants consuming 0.8g/kg bodyweight of carbohydrate an hour before cycling had significantly less fat oxidation during the session. Researchers attributed this to the blunting of lipolysis that was caused by the insulin release. From a practical standpoint, this could mean having breakfast after your morning workout.
Increased blood flow to abdominal region during fasting.
In a 2007 study, participants had a 50% increase in abdominal blood flow after a 72 hour fast. This blood flow was suggestive of increased lipolysis of abdominal adipose tissue (belly fat)!
However, if you’re looking to achieve optimal fat loss from training while intermittent fasting, you are more susceptible to muscle loss. This is because training itself is catabolic, meaning that rep after rep set after set you are continuously tearing away at your muscles. If not careful, you can actually start breaking down muscle to be used as an energy source!
This problem can be avoided by supplementing with BCAA’s during/ right before your workout. Leucine (the most widely studied BCAA) is well known to stimulate protein synthesis and reduce protein breakdown.
Because BCAA’s are already in their simplest amino acid form, they bypass the liver and enter the bloodstream directly. This means they can be utilized within minutes after ingestion, unlike other forms of protein like whey and casein.
For this reason, BCAA’s offer muscle sparing and protein synthesis benefits before, during, and after training!
If you are looking for an opportunity to put this theory to the test, stop by the Positive Image Fitness Studio for any one of our early morning sessions!